1. Field of the Invention
The present invention relates to a method of producing a semiconduction device, and more particularly to a method of producing a bipolar CMOS device for comprising a unipolar CMOS transistor with a polysilicon gate and a self-aligned NPN and VPNP transistor on a same chip.
2. Description of the Prior Art
In a conventional method of producing a bipolar CMOS device, as a bipolar NPN and VPNP transistor don't be self-aligned with an emitter and base, it is inferior to a self-aligned transistor in a packing density and an operating speed.
Also, a lateral bipolar NPN and PNP transistor is inferior to a vertical bipolar NPN and PNP transistor in a current handling capability and an operating speed.